In solar cell modules, the solar cells have surface electrodes, to which the wiring members (also called electro-conductive interconnect members or ribbons) are connected for extracting power from the cells. The wiring members are usually in the form of metal strips (such as Cu strips) and they are often connected to the surface electrodes by soldering. However, since relatively high temperatures are necessary for such soldering, stresses are applied to the connect structure due to the difference in co-efficiency of thermal shrinkage among the semiconductor structure responsible for power generation, the surface electrodes, the solder, and the wiring members. Such thermal stresses can cause the solar cell to be warped and cracked.
To solve this problem, people have proposed the use of polymer-based electrically conductive adhesives in place of solder to connect the wiring members with the surface electrodes of the solar cells. Such polymer-based electrically conductive adhesives typically are comprised of insulating polymers (such as, epoxy, acrylic, phenoxy, polyimide, or silicone) and electro-conductive particles (such as Ag particles) (see, for example, U.S. Patent Publication Nos. 2010/0147355 and 2012/0012153). And among them, silicone-based electrically conductive adhesives are more preferred than epoxy-based electrically conductive adhesives due its low modulus. However, it is found that, silicone rubber has a much higher coefficient of thermal expansion (CTE) than the electro-conductive particles, which can lead to a decrease in power output of the solar modules upon thermal cycling. Thus, there is still a need to develop novel polymer-based electrically conductive adhesives that could maintain its efficiency after thermal cycling.